Superheater



Oct. 25, 1932.

D. W. RUDORFF SUPERHEATER Filed March 5, 1931 l, 4 mm.,

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ATTORNEY Patented Oct. Z5, 1932 UNITI-:D STATES DAGOBER'T W. nunonrr,

SUPERHEATEB.-

Application med March 5,

This invention relates tol devices forregulating the temperature of superheated steam and has for kits object the provision of an improved apparatus and method for this purpose. The invention is illustrated in the dra-wing accompanying the present specification in which drawing Y' Fig. 1 shows a fragmentary vertical longitudinal section through a water-tube kboiler lo equipped with my invention;

Fig. 2 is a cross-section on Fig. 1; v

Figs. 3 to 6 are transverse sectional views ofy different forms of the elements of the 1 structure used to carry out my invention; y, Figs. 7 to 10 are four further views showingdiiferent forms of groups of elements which may be used to carry out the invention. The invention, as briefly pointed -out o above, relates to the regulation of the temperature of superheated steaml and for the purpose of illustrating a source of superheated steam I show a horizontal water-tube cross drum type of boiler. The setting 1 in- 25 closes the furnace 2 below the water `tube 3, the latter being connected to lower headers 4 and upper headers 5. Water from the steam and water drum 6 iscarried toy the headers 4 through the pipes on nipples 7 and a steam and water mixture is carried through line `2-2 of 'the pipes 8 back to the steam and water drum 6. Baiiing Q'directs the products of combustion from the furnace 2 on their way. to the stack connection (not shown).

y6 is carried b v means of the pipe 10 tothe superheater inlet header. 11. This header delivers the steam to a series ofk superheater elements 12 which are arranged inside ofthe o furn'ace in a manner presently to be de? scribed to absorb heat from the furnace and thereby to superheat thesteam. The other ends of the tubular superheater elements 12 are connected to the outlet header 13 whence the steam is taken to the point of consump- The `steam u ,that is liberated in the steam andwater drum l 1931. Serial No. 520,205.

Instead, however, of arranging kthe bare ,superheater elements 12 in a row against the furance wall as has been doneheretofore, I arrange them inside of acasing or casings,

.which may ttke a variety of forms. Inthe 4form of the invention illustrated in Figs, 1

and y2, Athe superheater elements 12 are each placed in a casing 14. vrThis casing isa closed chamber havinga connection 15 to a container y16 arranged at a somewhat higher.- level.v -Each superheater elementA 12 is, in the form shown, made up of two branches connected at their lower ends by areturn bend. Both of the branchesv pass through `header or manifold 18 which communicates vwith the water spacel of the steam and water drum by means lof the pipe 19, whereas thefgn5 upper ends of the pipe 17 are connected to a common manifold or header 2O which is in communication by means of the pipe 21 with the steam space of thedrum 6. In the pipe 19 there is preferably placed a valve 22shownV in Fig. 1 as of a thermostatic type acting in response tothe temperature of the steam` in header 13. For this purpose a thermostatic element is shown at 23 within the header 13 connected to the valve operating mechanism ofthe valve 22 by means of the pipe 24.

The inside of each casing 14 isfilled with a metal which will remain iiuid at thetemperatures involved, preferably such a metal as Woods metal. The metal Vis filledy in 9 through the chamber 16 and its level is maintained somewhere within this chamber 16.

The operation of the device is as follows: The Walls of the casings 14 which lie on the side toward the furnace absorb heat prinf ycipally by radiation and to a slighter degree by convection and transmit the heat to the melted metal within. This metal gives up heat to the steam flowing through the units 12 as well as to the water within the tubes 17 o l ings 14 would be injured. During periods of firing up and at other times when the Vsuperheater and the casings 14 require protection, the valve 22 will be wide open so that the maximum `amount of heat abstraction by means of water in the tubes 17 can be obtained. The

superheater is thereby protected even with no steam flowing through it,-a condition which exists particularly during firing upv periods.

After steam has begun to be liberated in drum 6 and to be drawn of from header 13, this steam will itself in part protect the superheater tubes and the casings 14. Under some conditions it may be vunnecessary to retain any Water in the tubes 17 The valve 22 can therefore under such conditions be closed entirely, the water in the tubes 17 being allowed to evaporate without being replenished. The maximum degree of superheat will then be obtained. If it is desired to lower the degree of superheat somewhat, the valve 22 is opened partly, thereby admitting some water into the tubes 17. If it is admitted at the right rate, the tubes 17 will not be filled entirely with Water and the cooling effect will be confined particularly to the lower part of thearrangement. In this way, the steam will not have as high a temperature upon delivery to the header 13 as it would were there no water present in the tubes 17. By opening the valve 22 to a further or lesser degree, the temperature of the steam can be anything desired within limits. Preferably, the valve 22 is given its position automatically in response to the steam temperature in header 13 by the thermostatic arrangement described above, including the thermostatic element 23, the valve 22, and the connecting pipe 24. This is a perfectly well-known arrangement and it is therefore believed unnecessary to describe it in any detail.

It will beclear that a number of variations are possible in the general arrangement without losing the real inventive thought. Whereas in the form just described and illust-rated in Fig. 2, thesuperheater tubes and the water tubes lie within the casings 14 (this arrangement being repeated in Fig. 3). A structure like that in Fig. 4 may be used. I-Iere the superheater tubes 12 are arranged in the same general relation to the water tube 17 as in the form first described but instead of lying inside of the casing they are connected by means of plates to form an interior triangular space 25 and this space is filled with the melted metal. It will be seen that the action of the apparatus is in a general way similar to that'of the form lirst described although the superheater elements are here exposed to a little more severe conditions and the cooling effect of the tube 17 is not as great.

In Fig. 5 is shown a form which may be regarded as a combination of the first two. The superheater pipes 12 here lie within the casing but the pipe 17 lies in the same relative positionas in Fig. 4, that is, it has the two longitudinal edges of the casing welded to it in such a manner that the tube lies partly within and partly without the casing. The melted metal is of course in the space 25.

In Fig. 6 the superheater tubes are in the relative position they are in Fig. 4 and the water tube is placed entirely within the space 25.

Instead of having a separate casing for each superheater element and its associated water tube, a number of these elements and tubes may be placed in a single casing. This is illustrated in Fig. 7 where the casing 14a' incloses a plurality of superheater elements 12 and water tubes 17. The space 25a is here filled with melted metal. In Fig. 8 the space 25a is defined by a plurality of superheater elements 12 and water tubes 17 connected together by a series of plates to form a closed chamber as will be clear from an inspection" of the ligure.

In Fig. 9 the superheater elements 12 lie entirely inside and the water tubes 17 partly inside and partly outside of the chamber 25a,

whereas in Fig. 10 the arrangement is re-lV versed, the water tubes 17 lying completely within andthe superheater tubes 12 partly within and partly without the space 25a.

I claim:

1. In apparatus of the class described, the

combination of a structure comprising a re-fno a steam superheater comprising a structure exposed to heat from the furnace and comprising a receptacle, a liquid metal in said receptacle, and two conduits in heat transferring relation to said liquid metal; means of one of said conduits; means to take steam away from the other end of said conduit; and means to circulate a cooling fluid at a controlled rate through the other conduit.

to convey steam from the boiler to one end 712e 4. Apparatus in accordance with claim 3,13o

. steam from the boiler to one end of said conduit, means to convey it away from the other end of the conduit, a second conduit extendl ing through but not opening into the liquid metal in the casing, means to introduce water from the boiler into one end of said second conduit, and means to convey back to the boiler from the other end of the second conduit any steam forming in it.

6. Apparatus in accordance with claim 5 and further comprising a thermostatically controlled valve in the means supplying water to the second conduit and regulating the quantity in response to temperature conditions in the steam leaving the first conduit.

7. In a radiant type superheater, means to protect the superheater at times when no steam or an insufficient quantity of steam is flowing through it, comprising water cooled pipes, liquid metal contacting with the superheater and wtih the water cooled pipes, and means to contain saidliquid metal.

8. In a radiant type superheater comprising a tubular superheater element through which the steam Hows, means to protect the element at times when no steam or insuicient steam is flowing through it comprising a water cooled pipe, a casing surrounding the element and the pipe, and a liquid metal filling the space in the casing outside of the element and the pipe.

9. In a radiant type superheater comprising a tubular superheater element through which the steam flows, means to regulate the temperature of the steam at the outlet of the element comprising a pipe, a casing sur-Y rounding the element and the pipe, a liquid metal filling the space in the casing outside of the element and the pipe, and means to introduce a cooling medium into the pipe at a. rate responsive to the temperature of the steam at the outlet from the element.

10. In apparatus of the class described, the combination of a boiler, a furnace therefor, an alined series of elongated metallic casings arranged in upright position adjacent to one wall of the furnace, a receptacle above and in communication with the casings, a superheater element extending into each casing but not opening into it, means to deliver steam from the boiler to and take it away from the elements, a pipe extending lengthwise through each casing without opening into it, means to deliver water from the boiler to the lower ends of the plpes and to deliver steam from the Aupper ends to the boiler drum, a thermostatically controlled valve inthe means supplying water to the pipes operative in response to the temperature of the steam at the outlet from the elements, and liquid metal filling the receptacle and the .space in the casing outside of the elements and the pipes.

i DAGOBERT W. RUDORFF. 

